It’s hard to argue that Audi has been a pioneer in bringing LEDs to the mass market. What is now seen in just about every vehicle segment and in every brand was once a novelty, seen only at the debut of the R8 back in 2007. Since it has become the hottest trend in exterior design, Audi has been attempting to roll out new lighting technologies, and is being stonewalled by U.S. safety regulators.

Audi is currently trying to win approval to sell a new type of sequential forward turn signals for the 2015 Audi A8, when it goes on sale in the American car market. This is similar to the sequential rear corner signals found on the Ford Mustang. The main difference is that the first of the three lights in a Mustang signal is the minimum legal size, the rest don’t matter. Meanwhile, the individual lights in the sequential Audi signals are too small too meet regulations.

It is only the latest roadblock in Audi’s efforts to bring new lighting to the U.S. market. In February, the National Highway Transportation Safety Administration informed Audi that its Matrix Beam headlights would not be allowed in the U.S. These lights operate as high beams and dim when an oncoming vehicle is approaching. Here is a video with both technologies in action:

According to the Automotive News report, Toyota filed a petition to have the NHTSA rewrite its rules on lighting. The way the agency is structured, Audi’s efforts are pretty much frozen until the Toyota request is addressed, which could take years.

As of now Audi can sell its new A8 with both the sequential signals and the auto-dim headlights. But for the immediate future, the prospect of bringing these technologies to American cars looks dim.